JPH03121300A - Jet pump - Google Patents

Abstract

PURPOSE:To suppress injection noise of fuel at a low level when a lot of excessive fuel is returned from an engine, and prevent generation of a fault of engine stopping or the like, by providing respectively a variable nozzle opening on a nozzle and a variable ejection opening on a diffuser. CONSTITUTION:A nozzle 2 has a return side fuel flowing-in opening 2a for flowing-in excessive fuel, and a variable nozzle opening 2b for injecting the excessive fuel. In the variable nozzle 2b, the lower end of the nozzle 2 is formed thinner than the thickness of an upper end and an intermediate part thereof, and an aperture (d) is enlarged in proportion to the flowing amount of the excessive fuel. A diffuser 3 is provided with a nozzle engaging part 3a, a cylindrical part 3c for flowing-in fuel, and a variable ejection opening 3e for discharging the fuel on a return side and bypass side. In the variable ejection opening 3e, the lower end of the diffuser 3 is formed thinner than the thickness of the nozzle engaging part 3a and the cylindrical part 3c for flowing-in the fuel, and an aperture D thereof is enlarged in proportion to the flow amount of the excessive fuel and fuel in a sub side tank, which is sucked into a negative pressure space 3d.

Description

[Detailed description of the invention] [Purpose of the invention]

(Industrial Application Field) The present invention relates to a jet pump that is attached to, for example, a saddle-shaped fuel tank of an automobile and is used to draw in fuel from a bypass side using fuel from a return side. (Prior Art) Conventionally, as the above-mentioned jet pump, for example, the fourth
There was something shown in the figure. The jet pump 51 shown in the figure is used by being attached to the main side tank of a saddle-shaped fuel tank of an automobile.
a nozzle 52 made of hard synthetic resin (for example, POM);
The diffuser 53 is also made of hard synthetic resin (for example, POM). The nozzle 52 has a return-side fuel inlet 52a at its upper end through which surplus fuel of the engine flows in, and a nozzle port 52b at its lower end through which the surplus fuel is injected. Further, this nozzle 52 is integrally provided with a fuel inflow cylindrical portion 52d having a bypass side fuel inlet 52c at the upper end into which fuel flows from the sub-side tank of the saddle-shaped fuel tank. On the other hand, the diffuser 53 has a nozzle fitting part 53a into which the nozzle part is fitted with sufficient margin when the nozzle 52 is attached, and the whole forms a negative pressure space 53b. There is. Further, at the lower end of the diffuser 53, a fuel discharge port 53c for discharging fuel on the return side and fuel on the bypass side is provided continuously to the nozzle fitting portion 53a. The jet pump 51 supplies return-side fuel that flows from the return-side fuel inlet 52a of the nozzle 52 and becomes a swirling flow by the swirl vanes 54 provided above the nozzle portion from the nozzle port 52b to the nozzle fitting portion. 53a, a negative pressure is generated in the negative pressure space 53b, and the suction force generated at this time causes the bypass side fuel inlet 52c to
The fuel on the bypass side flows in from the fuel outlet 53, and the fuel on the bypass side is discharged from the fuel discharge port 53c of the diffuser 53 together with the fuel on the return side. (Problems to be Solved by the Invention) However, in the above-described conventional jet pump 51,
The return side fuel flow rate is determined by the nozzle port 52b of the nozzle 52.
If the proper flow rate in the nozzle port 52b is exceeded,
A large amount of fuel is violently injected, and this injection noise may cause discomfort to the driver and passengers.At this time, as the pressure in the nozzle 52 increases, the pressure in the return pipe increases. However, since the engine speed becomes extremely high, problems such as engine stoppages may occur. In addition, conventionally, the flow rate of the return side fuel and the bypass side fuel sucked into the negative pressure space 53b by the injection of the return side fuel is equivalent to the carburetor usage rate and the vehicle using the electronically controlled fuel injection valve. For certain reasons, the nozzle port 52b and the fuel discharge port 53 have sizes suitable for the usage rate of the carburetor.
A jet pump 51 having a jet pump 51 having a jet pump 51, a nozzle port 52b and a fuel discharge port 5 of a size suitable for a vehicle using an electronically controlled fuel injection valve.
Since it was necessary to manufacture and manage the jet pump 51 with the jet pump 3c separately, there was a problem in that these processes required a lot of time and effort. (Purpose of the Invention) This invention was made by focusing on the conventional problems mentioned above. For example, when used in a saddle-shaped fuel tank of an engine, when a large amount of surplus fuel is returned from the engine. However, it is possible to suppress the fuel injection noise generated at this time, and prevent malfunctions such as engine stoppage.In addition, it is possible to reduce the carburetor usage rate and the performance of cars using electronically controlled fuel injection valves. The purpose is to provide a jet pump that can be applied to any of the above.

[Structure of the invention]

(Means for Solving the Problems) The present invention includes a nozzle that injects a fluid on the return side, and a negative pressure space formed by the injection of the fluid to suck the fluid from the bypass side, and a nozzle that injects the fluid from the nozzle. In the jet pump equipped with a diffuser for discharging fluid on the return side and a sucked fluid on the bypass side, the nozzle has a variable nozzle opening whose nozzle discharge opening expands in proportion to the flow rate of the fluid passing through the return side. In addition, the diffuser is provided with a variable discharge port that expands in proportion to the flow rate of the return-side fluid injected from the nozzle and the bypass-side fluid sucked into the negative pressure space. The jet pump having such a configuration is used as a means to solve the conventional problems, and in one embodiment, the opening area of the variable nozzle opening is set to A1. When the opening area of the variable discharge port is A2, when the flow rate Q of the fluid on the return side is 501/hr or less, At/
A2 is in the range of 0.23 to 0.28, and when the flow rate Q of the fluid on the return side is 50 m/hr or more, A, /
It is characterized in that A2 is set within the range of 0.28 to 0.32. In this case, the nozzle and diffuser may be formed integrally or separately. In addition, it is preferable that both the nozzle and the diffuser be made of an elastic material such as synthetic rubber. In particular, when this jet pump is used in a saddle-shaped tank of an engine, nitrile rubber (NBR), which has excellent oil resistance, is used. ) is preferable. (Operation of the invention) Since the jet pump according to the present invention has the above-described configuration, when the flow rate of fluid on the return side is large, the variable nozzle opening of the nozzle expands. The fluid on the return side that is injected from the port is not accelerated more than necessary, and the noise of the fluid that is ejected from the variable nozzle port becomes small, and the increase in pressure on the return side is also suppressed. That will happen. In addition, when this jet pump is used in a saddle-shaped fuel tank of an engine, since this jet pump has a variable nozzle port and a variable discharge port, the injection of fuel on the return side and the fuel on the return side A jet pump is suitable for cars using a carburetor, where the flow rate of fuel on the bypass side drawn into the negative pressure space is small, and is suitable for cars using electronically controlled fuel injection valves, where the flow rates of fuel on the return side and fuel on the bypass side are high. will also be suitable. (Example) Hereinafter, the present invention will be explained based on the drawings. 1 to 3rgJ show an embodiment of a jet pump according to the present invention, and in this embodiment, a case where the jet pump according to the present invention is attached to a saddle-shaped fuel tank of an automobile is illustrated. That is, the jet pump 1 shown in the figure includes a nozzle 2 that injects surplus fuel of the engine, that is, fluid on the return side,
The diffuser 3 is integrally formed with a diffuser 3 that sucks the fuel in the sub-side tank, that is, the fluid from the bypass side by injecting the surplus fuel, and discharges the surplus fuel and the fuel in the sub-side tank. In this embodiment, it is integrally formed of nitrile rubber. The nozzle 2 has a return side fuel inlet 2a at the upper end through which surplus fuel flows in, a variable nozzle opening 2b at the lower end through which the surplus fuel is injected, and a swirling hole in the middle part for generating a swirling flow. It is equipped with wings 2C rotatably. At this time, the variable nozzle port 2b is formed so that the wall thickness at the lower end of the nozzle 2 is thinner than the wall thickness at the upper end and the middle portion, so that the variable nozzle port 2b has a flow rate proportional to the flow rate of surplus fuel flowing from the return side fuel inlet 2a. In this embodiment, when the flow rate of fuel on the return side is 30 l/hr, the diameter d is 1.5 mm, that is, the opening Area is 1.74mm2
The variable nozzle port 2b has a return side fuel flow rate of 1
At 40 l/hr, the diameter d is 2.2 m.
m, that is, the opening area is expanded to 3.75 mm2. On the other hand, the diffuser 3 includes a funnel-shaped nozzle fitting part 3a into which the lower end portion of the nozzle 2 is fitted with a sufficient margin, and a funnel-shaped nozzle fitting part 3a that is continuous with the nozzle fitting part 3a and into which fuel from the sub-side tank flows into the upper end. A fuel inflow cylindrical part 3c having a bypass side fuel inlet 3b, and a nozzle fitting part 3.
A and the lower end portion of the fuel inflow cylindrical portion 3c collectively form a negative pressure space 3d, and a variable valve that discharges fuel on the return side and fuel on the bypass side to the lower end side of the nozzle fitting portion 3a. It has a discharge port 3e. In this case, the variable discharge port 3e is similar to the variable nozzle port 2b,
By forming the wall thickness of the lower end of the diffuser 3 thinner than the wall thickness of the nozzle fitting part 3a and the fuel inflow cylindrical part 3C, the flow rate of surplus fuel and fuel in the sub-side tank sucked into the negative pressure space 3d. The aperture can be enlarged in proportion to the diameter, as shown by the imaginary line in Figure 2.
In this embodiment, when the flow rate of the return side fuel jetted from the variable nozzle port 2b is 301/hr, the aperture is 3.
．． 0 mm, that is, the variable discharge port 3e whose opening area is 6.98 mm2 has a return side fuel flow rate of 1401 mm2.
/hr, the diameter is 4.0 mm, that is, the opening area is expanded to 12.40 mm2. As shown in FIG. 3, this jet pump 1 includes a saddle-shaped fuel tank 1 to which a fuel pump 11 is attached.
The return side fuel inlet 2a of the jet pump 1 is installed in the main side tank 12& of the engine 14, which is connected to the fuel pump 11 via a pipe 13 Surplus fuel return port 1
4a via a pipe 15, and the bypass-side fuel inlet 3b communicates with the vicinity of the bottom of the sub-side tank 12b of the fuel tank 12 via a bypass pipe 16. Next, the operation of the jet pump 1 described above will be explained. First, when the engine is started, the fuel pump 11 operates and the main side tank 12 of the fuel tank 12
The fuel stored in a is sucked up and delivered to a fuel supply section 14 via a pipe 13. Next, the surplus fuel returned from the surplus fuel return port 14a of the fuel supply section 14 via the pipe 15 is transferred to the jet pump 1.
The fuel flows into the nozzle 2 through the return side fuel inlet 2a of
From there, it is injected into the nozzle fitting part 3a of the diffuser 3. Here, when the flow rate of the surplus fuel is large, the diameter d of the variable nozzle port 2b expands as shown by the virtual line in FIG. 2 in proportion to the flow rate of the surplus fuel, so the surplus fuel is not necessary. Since the ink is injected from the variable nozzle port 2b without being increased in speed, the injecting noise can be suppressed to a low level, and the pressure in the return side piping 15 can be prevented from increasing. As the surplus fuel is injected from the variable nozzle port 2b, a negative pressure is generated in the negative pressure space 3d of the diffuser 3, and a suction force is generated, and the bypass fuel is stored in the sub-side tank 12b of the fuel tank 12. The side fuel flows from the bypass side fuel inlet 3b through the fuel inflow cylindrical part 3C via the pipe 16 and into the negative pressure space 3d. Next, the fuel on the bypass side is discharged from the variable discharge port 3e of the diffuser 3 to the main side tank 12& of the fuel tank 12 together with the fuel on the return side. Here, too, when the flow rate of surplus fuel injected from the variable nozzle port 2b is large, the diameter of the variable discharge port 3e increases in proportion to this surplus fuel as shown by the imaginary line in FIG. Therefore, it is possible to prevent fuel from being violently jetted out from the variable discharge port 3e. In this way, in the jet pump 1, the variable nozzle port 2b of the nozzle 2 and the variable discharge port 3e of the diffuser 3 expand in proportion to the flow rate of fuel on the return side, so that fuel is always injected and discharged in an optimal state. Therefore, the time to start sucking up the fuel on the bypass side can be brought forward, and the suction performance can be improved. When this jet pump 1 is used as a fuel supply part in a car that uses an electronically controlled fuel injection valve, the flow rates of fuel on the return side and fuel on the bypass side will be lower than in a car that uses the above-mentioned carburetor. However, as mentioned above, the diameters d and D of the variable nozzle port 2b of the nozzle 2 and the variable discharge port 3e of the diffuser 3 expand in proportion to the flow rate of the fuel on the return side, so if the carburetor is used, This jet pump 1 is also suitable for vehicles using electronically controlled fuel injection valves because it is possible to suppress the injection noise to a low level and to prevent the pressure in the return side piping 15 from increasing. Become something. In addition, in this embodiment, the jet pump 1 according to the present invention is
Although the case where the jet pump is attached to the saddle-shaped fuel tank 12 is illustrated, it is also possible to apply this jet pump to a drainage tank or the like. Further, the detailed configuration of the jet pump 1 according to the present invention is not limited to the above-described embodiment.

【Effect of the invention】

As explained above, according to the present invention. A nozzle that injects fluid on the return side, and a negative pressure space formed by ejecting the fluid to suck fluid from the bypass side, and the fluid on the return side injected from the nozzle and the sucked fluid on the bypass side. In the jet pump, the nozzle is provided with a variable nozzle opening whose nozzle discharge opening expands in proportion to the flow rate of fluid that passes through the return side, and the diffuser is provided with a variable nozzle opening that expands in proportion to the flow rate of fluid that passes through the return side. Since the configuration includes a variable discharge port that expands in proportion to the flow rate of the fluid on the return side and the fluid on the bypass side sucked into the negative pressure space,
For example, when this jet pump is used in a saddle-shaped fuel tank and a large amount of surplus fuel is returned from the engine, the fuel injection noise can be suppressed, causing discomfort to the driver and passengers. In addition, it is possible to prevent the pressure from increasing in the return piping, which prevents problems such as engine stoppage. Since the present invention can be applied to both cars and vehicles using electronically controlled fuel injection valves, an extremely excellent effect is brought about in that it is possible to reduce the labor involved in manufacturing and management.

[Brief explanation of drawings]

FIG. 1 is an explanatory longitudinal cross-sectional view showing one embodiment of the jet pump according to the present invention, and FIG. 2 is an enlarged view of the variable nozzle port of the nozzle and the variable discharge port of the diffuser in the jet pump shown in FIG. Partially enlarged longitudinal cross-sectional explanatory diagram shown in Figure 3.
This figure is a schematic explanatory view of a saddle-shaped fuel tank to which the jet pump of FIG. 1 is attached, and FIG. 4 is a vertical cross-sectional explanatory view showing a conventional jet pump. 1... Jet pump, 2... Nozzle, 2b... Variable nozzle opening, 3... Diffuser. 3d... Negative pressure space, 3e... Variable discharge port.

Claims (2)

[Claims] (1) A nozzle that injects fluid on the return side, and a negative pressure space formed by ejecting the fluid to suck fluid from the bypass side, and the fluid on the return side injected from the nozzle and the sucked bypass side. In the jet pump, the nozzle is provided with a variable nozzle opening whose nozzle discharge opening expands in proportion to the flow rate of the fluid passing through the return side, and the diffuser is provided with a variable nozzle opening that expands in proportion to the flow rate of the fluid passing through the return side. A jet pump comprising a variable discharge port that expands in proportion to the flow rate of the injected return-side fluid and the bypass-side fluid sucked into the negative pressure space. (2) When the opening area of the variable nozzle port is A_1 and the opening area of the variable fluid discharge port is A_2, when the flow rate Q of the fluid on the return side is 50 l/hr or less, A_1/A_2
= in the range of 0.23 to 0.28, and when the flow rate Q of the fluid on the return side is 50 l/hr or more, A_1/A_2 is set to be in the range of 0.28 to 0.32. The jet pump according to item (1).